The proposed research is directed toward significantly improving mass spectrometric techniques for the analysis of involatile biomolecules, in general, and oligopeptides in particular. Particular emphasis will be given to field desorption, laser desorption, and flash desorption-electron ionization techniques. Research already accomplished has provided important experimental and theoretical results. Most significantly, analyses of the identities of ion species observed in mass spectra produced by different techniques have led to the formulation of a unifying theory to describe the processes associated with the desorption of involatile biomolecules from surfaces in the form of neutral molecules and ions. The specific experimental aims of the proposed research are (a) to test the predictions of the aforementioned theory, (b) to utilize newly gained knowledge of fundamental desorption and ionization processes in optimizing experimental protocols for mass spectrometric analysis of underivatized oligopeptides and other important biomolecules under conditions typical for use with biological isolates, and (c) to determine molecular weight and structural information about important polar biomolecules procured through ongoing and new collaborative arrangements.